#!/usr/bin/env python3 ''' _/_/ _/ _/ _/ _/_/ _/ _/_/ _/_/_/ _/_/_/ _/_/_/_/ _/_/_/_/ _/_/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/ _/_/_/ _/ _/_/_/ _/ _/_/_/ _/ _/_/ Copyright 2025 bdunahu Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License. Commentary: Aergia is a sampling based profiler based off of SCALENE by Emery Berger and the UMASS Plasma Lab (https://github.com/plasma-umass/scalene). It is not particularly informative, but unlike SCALENE or other sampling-based profilers I could find, reports the wall-time each asyncio await call spends idling. (yappi can profile asyncio, but only report time spent in each function. Instrumentation-profilers cannot do this without adding very large overhead). The goal behind Aergia is to eventually have these features, or similar, merged into SCALENE. Code: ''' from collections import defaultdict, namedtuple from typing import Optional, Tuple from types import FrameType import argparse import asyncio import signal import sys import threading import time import traceback import gc from types import AsyncGeneratorType orig_thread_join = threading.Thread.join def thread_join_replacement( self: threading.Thread, timeout: Optional[float] = None ) -> None: ''' We replace threading.Thread.join with this method which always periodically yields. ''' start_time = time.perf_counter() interval = sys.getswitchinterval() while self.is_alive(): orig_thread_join(self, interval) # If a timeout was specified, check to see if it's expired. if timeout is not None: end_time = time.perf_counter() if end_time - start_time >= timeout: return None return None threading.Thread.join = thread_join_replacement # a tuple used as a key in the sample-dict Sample = namedtuple('Sample', ['file', 'line', 'func']) class Aergia(object): # a key-value pair where keys represent frame metadata (see # Aergia.frame_to_string) and values represent number of times # sampled. samples = defaultdict(lambda: 0) # number of times samples have been collected total_samples = 0 # the (ideal) interval between samples signal_interval = 0.0 # the timestamp which the last sample was taken last_sample = None # the current task for the loop being processed current_task = None # if we should profile currently running tasks do_profile_current = False @staticmethod def __init__(signal_interval, do_profile_current): Aergia.signal_interval = signal_interval Aergia.do_profile_current = do_profile_current @staticmethod def start(): '''Turns on asyncio debug mode and sets up our signals. Debug mode must be on by default to avoid losing samples. Debug mode is required to view the current coroutine being waited on in `Aergia._get_idle_task_frames'. The TimerHandler object otherwise does not keep track of a _source_traceback. ''' Aergia.last_sample = time.perf_counter() signal.signal(signal.SIGALRM, Aergia._idle_signal_handler) signal.setitimer(signal.ITIMER_REAL, Aergia.signal_interval, Aergia.signal_interval) @staticmethod def stop(): '''Stops the profiler.''' signal.setitimer(signal.ITIMER_REAL, 0) @staticmethod def clear(): Aergia.total_samples = 0 Aergia.samples = defaultdict(lambda: 0) @staticmethod def get_samples(): '''Returns the profiling results.''' return Aergia.samples @staticmethod def print_samples(): '''Pretty-print profiling results.''' if Aergia.total_samples > 0: print(f"{'FILE':<30} {'FUNC':<30}" f" {'PERC':<8} {'SEC':<10}") for key in Aergia._sort_samples(Aergia.samples): Aergia.print_sample(key) else: print("No samples were gathered. If you *are* using concurrency, " "this is likely a bug and you may run Aergia again.") @staticmethod def print_sample(key): '''Pretty-print a single sample.''' sig_intv = Aergia.signal_interval value = Aergia.samples[key] print(f"{Aergia._tuple_to_string(key)} {value * 100 / Aergia.total_samples:.3f}% " f" {value*sig_intv:.6f}") @staticmethod def _idle_signal_handler(sig, frame): '''Obtains and records which lines are currently being waited on.''' curr_sample = time.perf_counter() passed_time = curr_sample - Aergia.last_sample keys = Aergia._compute_frames_to_record() for key in keys: Aergia.samples[Aergia._frame_to_tuple(key)] += passed_time Aergia.total_samples += passed_time Aergia.last_sample = curr_sample @staticmethod def _compute_frames_to_record(): '''Collects all stack frames which are currently being awaited on during a given timestamp, as well as those which are currently executing. Note that we do NOT need to walk back up the call-stack to find which of the user's lines caused the await call. There is NEVER a previous frame, because idle frames aren't on the call stack! Luckily, the event loop and asyncio.all_tasks keeps track of what is running for us.''' loops = Aergia._get_event_loops() # idle tasks frames = Aergia._get_frames_from_loops(loops) # current running frames if Aergia.do_profile_current: frames += Aergia._get_frames_from_threads() return frames @staticmethod def _get_event_loops(): '''Returns each thread's event loop, if it exists.''' loops = [] for t in threading.enumerate(): frame = sys._current_frames().get(t.ident) if frame: loop = Aergia._walk_back_until_loop(frame) if loop and loop not in loops: loops.append(loop) return loops @staticmethod def _walk_back_until_loop(frame): '''Walks back the callstack until we are in a method named '_run_once'. If this is ever true, we assume we are in an Asyncio event loop method, and check to see if the 'self' variable is indeed and instance of AbstractEventLoop. Return this variable if true.''' while frame: if frame.f_code.co_name == '_run_once' and 'self' in frame.f_locals: loop = frame.f_locals['self'] if isinstance(loop, asyncio.AbstractEventLoop): return loop else: frame = frame.f_back return None @staticmethod def _get_frames_from_loops(loops): '''Given LOOPS, returns a flat list of frames.''' return [ frames for loop in loops for frames in Aergia._get_idle_task_frames(loop) ] @staticmethod def _get_frames_from_threads(): frames = [sys._current_frames().get(t.ident, None) for t in threading.enumerate()] # process frames to remove those we do not track new_frames = [] for f in frames: if f is None: continue fname = f.f_code.co_filename while not Aergia._should_trace(fname): # walk the stack backwards until we hit a frame that is one # we should trace. if f: f = f.f_back else: break if f: fname = f.f_code.co_filename if f: new_frames.append(f) return new_frames @staticmethod def _frame_to_tuple(frame): '''Given a frame, constructs a sample key for tallying lines.''' co = frame.f_code func_name = co.co_name line_no = frame.f_lineno filename = co.co_filename return Sample(filename, line_no, func_name) @staticmethod def _tuple_to_string(sample): '''Given a namedtuple corresponding to a sample key, pretty-prints a frame as a function/file name and a line number.''' filename = \ (sample.file if len(sample.file) <= 25 else sample.file[-25:]) return f"{filename}:{sample.line}".ljust(30) + f"{sample.func:30}" @staticmethod def _sort_samples(sample_dict): '''Returns SAMPLE_DICT in descending order by number of samples.''' return {k: v for k, v in sorted(sample_dict.items(), key=lambda item: item[1], reverse=True)} @staticmethod def _get_idle_task_frames(loop): '''Given an asyncio event loop, returns the list of idle task frames. We only care about idle task frames, as running tasks are already included elsewhere.''' idle = [] # required later Aergia.current_task = asyncio.current_task(loop) for task in asyncio.all_tasks(loop): if not Aergia._task_is_valid(task) or task == Aergia.current_task: continue coro = task.get_coro() frame = Aergia._get_deepest_traceable_frame(coro) if frame: idle.append(frame) return idle @staticmethod def _get_deepest_traceable_frame(coro): '''Get the deepest frame of coro we care to trace. This is possible because each coroutine keeps a reference to the coroutine it is waiting on. Note that it cannot be the case that a task is suspended in a frame that does not belong to a coroutine, asyncio is very particular about that! This is also why we only track idle tasks this way.''' curr = coro deepest_frame = None while curr: frame, curr = Aergia._trace_down(curr) if frame is None: break if Aergia._should_trace(frame.f_code.co_filename): deepest_frame = frame # if this task is found to point to another task we're profiling, # then we will get the deepest frame later and should return nothing. # this is specific to gathering futures, i.e., gather statement. if curr is not None: tasks = getattr(curr, '_children', []) if any( Aergia._task_is_valid(task) for task in tasks ) or (tasks and all( # if all the tasks are done, getattr(task, '_state', None) == "FINISHED" for task in tasks )): return None return deepest_frame @staticmethod def _task_is_valid(task): '''Returns FALSE if TASK is uninteresting to the user. A task is interesting if it has actually started executing, and if a child task did not originate from it. ''' if not isinstance(task, asyncio.Task): return False if task._state != 'PENDING': return False coro = task.get_coro() # the task is not running and has not started running. # if this is the case, the associated coroutine will be 'waiting' # on the coroutine declaration. No! Bad! frame, awaitable = Aergia._trace_down(coro) if task != Aergia.current_task and \ (frame is None or awaitable is None): return False return True @staticmethod def _trace_down(awaitable) -> \ Tuple[Optional[FrameType], Optional[asyncio.Future]]: ''' Helper for _get_deepest_traceable_frame Given AWAITABLE, returns its associated frame and the future it is waiting on, if any.''' if asyncio.iscoroutine(awaitable) and \ hasattr(awaitable, 'cr_await') and \ hasattr(awaitable, 'cr_frame'): return getattr(awaitable, 'cr_frame', None), \ getattr(awaitable, 'cr_await', None) # attempt to obtain an async-generator # can gc be avoided here? refs = gc.get_referents(awaitable) if refs: awaitable = refs[0] if isinstance(awaitable, AsyncGeneratorType): return getattr(awaitable, 'ag_frame', None), \ getattr(awaitable, 'ag_await', None) if isinstance(awaitable, asyncio.Future): # return whatever future we found. return None, awaitable return None, None @staticmethod def _should_trace(filename): '''Returns FALSE if filename is uninteresting to the user. Don't depend on this. It's good enough for testing.''' # FIXME Assume GuixSD. Makes filtering easy if not filename: return False if '/gnu/store' in filename: return False if 'site-packages' in filename: return False if 'propcache' in filename: return False if '.pyx' in filename: return False if filename[0] == '<': return False if 'aergia.py' in filename: return False return True the_globals = { '__name__': '__main__', '__doc__': None, '__package__': None, '__loader__': globals()['__loader__'], '__spec__': None, '__annotations__': {}, '__builtins__': globals()['__builtins__'], '__file__': None, '__cached__': None, } if __name__ == "__main__": # parses CLI arguments and facilitates profiler runtime. parser = argparse.ArgumentParser( usage='%(prog)s [args] script [args]' ) parser.add_argument('-i', '--interval', help='The minimum amount of time inbetween \ samples in seconds.', metavar='', type=float, default=0.01) parser.add_argument('-a', '--async-only', help='Do not profile currently running tasks.', action='store_true') parser.add_argument('script', help='A python script to run.') parser.add_argument('s_args', nargs=argparse.REMAINDER, help='python script args') args = parser.parse_args() sys.argv = [args.script] + args.s_args try: with open(args.script, 'r', encoding='utf-8') as fp: code = compile(fp.read(), args.script, "exec") Aergia(args.interval, not args.async_only).start() exec(code, the_globals) Aergia.print_samples() Aergia.stop() except Exception: traceback.print_exc()